1. Field of the Invention
This invention relates to a valve assembly for use with air treatment apparatus; that is, apparatus which includes a matrix for exchanging heat and/or humidity present in air flowing therethrough.
2. Description of the Prior Art
With the increased recognition of the need for exchanging stale (and sometimes toxic) air within a room or other enclosure with fresh air from the outside, there have developed a variety of devices for accomplishing that exchange. One such device uses a slowly rotating heat recovery rotor through which parallel, but separate, air streams pass in countercurrent flow. Another such device employs a two-position valve for reversing air flow in ducts leading into the device from the outside.
One type of treatment apparatus has air as part of its operation a step in which air within a room or enclosure is exhausted to the outside. There is, therefore, the possibility, depending upon the structure of the device and its mode of operation, for stale exhaust air to be immediately drawn back into the air exchange device as "fresh" air. This occurrence may result from an inadequate porting arrangement to the outside air where stale air being exhausted remains in the vicinity of the fresh air inlet port or from inordinately long exhaust ducts leading to the outside, thereby creating a situation where stale air, instead of being exhausted to the outside, moves back and forth within an extended duct during cycling of the air exchanging device. A valve system that would minimize the co-mingling of exhaust air and fresh air would be useful in this application.
Another type of air treatment apparatus is one in which air having a relatively high moisture content (high humidity) is dried by passing the air through a matrix that absorbs or adsorbs moisture. This type of apparatus may require reactivation of the matrix when it has reached its moisture gathering capacity; such apparatus could benefit from a valve system that permits air flow in one path while impeding air flow in another path and then reverses.